1. Technical Field
The present invention relates to collapsible and extendable gravity-type conveyor systems. More particularly, the present invention relates to a gravity-type conveyor system which comprises a series of nestable sections, each of which having polymerized connecting side rails, which may be collapsed or extended with respect to one another.
2. Discussion
Conveyor systems are commonly used for delivering articles from one place to another and commonly over relatively large distances in warehouses, shipping areas, stores and the like. Some conveyor systems are permanent fixtures of such structures and include powered conveyor belts or an array of powered rollers. A variety of such conveyor systems and their components are known. For example, U.S. Pat. No. 5,205,400, issued on Apr. 27, 1993, discloses a belt system for transferring food. The system includes a rack which has a continuous conveyor belt suspended between two spaced apart rollers. The belt may be readily interchanged.
However, it is occasionally desirable to provide a method of conveying articles using a temporary system which may be collapsed for use in different areas. For example, it is frequently the case that goods must be delivered from a delivery vehicle such as a delivery truck to a receiving or unloading dock. In such situations the construction of a permanent conveyor system is undesirable and is frequently impossible. Instead, portable and collapsible conveyor systems are called upon to provide a method of delivering goods. These portable systems are typically not powered and rely on gravity for the movement of goods. To accomplish this task, an array of spaced apart, parallel rollers are provided between two side rails. The rollers are optionally positioned in a gradual incline between the receiving end and the delivery end such that goods deposited at the receiving end are able to travel the length of the conveyor (or of each component of the conveyor) without powered assistance. An example of one such system is disclosed in U.S. Pat. No. 5,350,048, issued on Sep. 27, 1994, which discloses a modular component system for assembly of material flow rails. The system includes a base made of selected ones of a plurality of interchangeable components which may be chosen for a particular application.
Although known systems have provided some solutions to the problems associated with portable conveyor systems, there remain many disadvantages. Of these is the problem of overcomplexity. The most practical portable conveyor system is one able to collapse onto itself by means of a nesting arrangement of each of the components. In this situation, each of the individual components of the system is connected to an adjacent component such that each component may be moved toward or away from the adjacent component without the components becoming disconnected. This arrangement requires an overabundance of individual parts, including, for example, a plurality of roller bearings and races.
An additional problem of known conveyor systems is one of resilience. Known systems are virtually entirely composed of one or more metals, typically aluminum and steel. The long side rails which provide support for the rollers are particularly susceptible to damage, particularly side impacts, which result from improper use or accidental impact. Regardless of the source, the resulting damage typically compromises the effective functioning of the collapsible system. For example, a side impact to an individual component of the known multi-component conveyor system often results in costly damage to the side rails. Once damaged, these components are difficult if not impossible to repair and the collapsing characteristic of the system is severely compromised as a result because both alignment and the slots for the bearings and other sliding mechanisms are altered.
Another problem of known collapsible conveyor systems is that of maintenance. Known systems made of metal require considerable upkeep in the way of lubrication and cleaning. Conveyor systems are exposed to a relatively harsh environment which includes severe dust and other material. Once lubricated to maintain sliding and rolling, this material adheres to the lubricant (typically a grease), resulting in slowed operation and accelerated wear on the moving parts. The only resolution according to known systems is constant cleaning and recleaning of the components which are generally difficult to reach.
Accordingly, an improved collapsible conveyor system remains wanting.